It has become relatively common for individuals to possess a number of different devices through which they communicate. For example, a person may have a home telephone, a wireless telephone, a pager, a personal digital assistant (PDA), and an office telephone to name a few. Today, it is common for a mobile device such as a cellular telephone or PDA to include both cellular (i.e., circuit switching) and data (i.e., packet switching) services, providing the user with the ability to wirelessly transmit and receive voice and data from the same device.
Presently, GSM (Global System for Mobile communications) is the wireless technology used in most of the world's mobile/wireless telephone networks. GSM is digital cellular technology that allows the transmission and reception of voice and data. GSM also allows the transmission of basic data services such as e.g., SMS (Short Message Service). Because GSM is used in over 200 countries worldwide, a GSM compatible telephone/PDA can be used outside of the user's own country or region. This is a major advantage of GSM.
Almost all of today's GSM networks include the GPRS (General Packet Radio Service) service. GPRS is IP (Internet Protocol) based and supports a wide range of enterprise and consumer applications. GPRS improves wireless data throughput rates, allowing users to have similar access speeds as typically found in dial-up modems. GPRS users are provided with advanced data services such as e.g., color Internet browsing, e-mail, video streaming, multimedia messaging and location-based services to name a few.
Further enhancements to GSM networks are provided by EDGE (Enhanced Data rates for GSM Evolution) technology. EDGE provides up to three times the data capacity of GPRS. EDGE users are provided with advanced wireless/mobile services such as e.g., the ability to download video and music clips, full multimedia messaging, high-speed color Internet browsing and e-mail.
Other wireless technologies include iDEN (Integrated Digital Enhanced Network), Code Division Multiple Access (CDMA) and CDMA2000 to name a few. iDEN combines the capabilities of a digital cellular telephone, two-way radio, alphanumeric pager and data/fax modem in a single network. iDEN is based on a time division multiple access (TDMA) and GSM architecture. CDMA uses a spread spectrum approach where each conversation is digitized and then tagged with a code. CDMA conversations are “spread” when sent and subsequently reassembled upon reception. CDMA technology allows multiple calls to be carried over one channel. CDMA2000 is an evolution of CDMA designed for narrowband transmissions.
The class of the mobile device determines which of the above voice/data capabilities the device has and how the capabilities may be used. For example, class A mobile devices can be connected to both GPRS and GSM services simultaneously. These devices can transmit/receive GPRS-type data at the same time the user is having a voice communication. Class B mobile devices, on the other hand, can be connected to both GPRS and GSM services, but may only use one service at a time. Class B devices can place or receive voice calls, or place/receive an SMS message (i.e., text message). During voice calls or SMS messaging, GPRS services are suspended and then resumed automatically after the call or SMS session has ended. Class C mobile devices are connected to either GPRS or the GSM voice service. A user needs to manually switch between voice and data services using the class C device.
When a wireless/mobile device user is using a non-class A wireless/cellular endpoint (i.e., the user is using a non-class A mobile device) to have voice communications with another party, the user loses the ability to send and receive data other than using SMS messages (e.g., text messaging). If the user of the non-class A device wishes to send an e-mail or initiate another data transfer (e.g., Internet browsing, file download, etc.), the user must disconnect the current communication with the other party before doing so. Once the user sends and/or receives the desired data, the user must callback the other party to continue their conversation; this is inconvenient to both parties while also adding the expense associated with the additional voice call. There is also the possibility that the other party will become engaged in another conversation and will be unavailable for the return call. The inability to exchange data while a voice communication is ongoing using a non-class A wireless endpoint is a significant drawback in the industry since it is estimated that over 90% of mobile device users are using non-class A devices.